Advice for a friend!

So I was hanging out with a friend last night and she told me that she has not had her period since the SPRING. So for about 6 months. She's 22 and usually pretty regular. She is not sexually active at all. She's been under huge amounts of stress with school and studying for GRE's, getting ready to move abroad for 6-8 months, finishing college, apply to grad schools, etc. 

She's thinking it's just stress and hasn't gone to see a doctor about it. From other parts of our conversation, it doesn't sound like she's eating enough, either. I do not believe she's intentionally restricting- she just doesn't feel hungry. 

To me, this all seems pretty serious. Once the main stressors are done (by December or January), she said she would see a doctor if her period has not started up again. I personally think that she should see one now. I've never heard of stress being so great that it stopped a period for 6/7 months before unless your hormones are completely unbalanced, which is bad for your health in general. 

I feel like I should encourage her more to see a doctor asap... but I don't want to cross boundaries, ya know? Does anyone have an advice? 

PS I posted anonymously just to preserve her privacy and mine.